Temporomandibular joint pain and dysfunction

Exploring the effect of disc displacement on the risk and severity of condylar erosion in adult temporomandibular disorder patients: A CBCT and MRI study

OBJECTIVE

The objective of the study was to investigate the relationship between types of disc displacement (DD) diagnosed by magnetic resonance imaging (MRI), and the risk (presence or absence) and severity of condylar erosion (CE) graded using cone-beam computed tomography (CBCT) in adult Temporomandibular disorders (TMD) patients.

METHODS

A total of 353 TMD patients (283 females, 70 males) underwent MRI scans to categorise DD as normal (NA), anterior displacement with reduction (ADDR), or anterior displacement without reduction (ADDNR). CE severity was graded on a scale of 0-3 (absence, mild, moderate or severe) using CBCT. To establish the plausibility and cut-off points for CE diagnosis, the severity of CE was then further divided into three classifications: Grade 0 versus 1 + 2 + 3; Grades 0 + 1 versus 2 + 3; Grades 0 + 1 + 2 versus 3. Logistic regression analysis was performed, adjusting for age, gender and joint correlation.

RESULTS

ADDNR significantly increased the risk of CE compared with NA (OR = 10.04, 95% CI: [6.41, 15.73]) and showed a significant increase in CE severity across all classifications (ORs = 10.04-18.95). The effects of ADDNR were significant in both genders (p < .001) and had a greater impact in females. ADDR was predominantly associated with mild CE.

CONCLUSIONS

ADDNR significantly increased the risk and severity of CE independent of gender when compared to NA, whereas ADDR was mainly associated with mild CE. Slight cortical discontinuity may represent a subclinical diagnosis requiring further investigation.

The reports of specific waking-state oral behaviours, including awake bruxism activities, and psychological distress have a dose-response relationship: A retrospective medical record study

OBJECTIVE

To investigate if there are dose-response relationships between self-reported waking-state oral behaviours, including awake bruxism, and three indicators of psychological distress (depression, anxiety, stress).

METHODS

The study sample consisted of 1,886 patients with function-dependent TMD pain. Relationships between six non-functional and six functional waking-state oral behaviours, scored on a 5-point ordinal scale, and the psychological factors were investigated using ordinal logistic regression.

RESULTS

Mean age was 42.4 (±15.3) years, 78.7% being female. The odds of reporting the higher categories of non-functional oral behaviours depended on the severity of depression, anxiety, and stress. Most OR coefficients followed a quadratic dose-response distribution, the others increased linearly as the severity of the psychological scales increased. Almost no such associations were found with normal jaw function behaviours.

CONCLUSION

Within the limitations of this study, it may be concluded that non-functional waking-state oral behaviours, including awake bruxism, and psychological distress have a dose-response relationship, with higher levels of distress being associated with higher reports of oral behaviours.

The effectiveness of botulinum toxin for temporomandibular disorders: A systematic review and meta-analysis

OBJECTIVE

The current body of research on utilizing botulinum toxin (BTX) to manage temporomandibular disorders (TMDs) has not yet yielded definitive conclusions. The primary objective of this study was to determine the effectiveness of BTX in pain reduction for TMDs compared to placebo and other treatments. The secondary outcomes evaluated were adverse events, maximum mouth opening, bruxism events, and maximum occlusal force.

MATERIALS AND METHODS

A literature search was performed on PubMed, Dimension Publication, Scopus, and Google Scholar. The RoB 2 tool was used for quality assessment. The mean differences in pain scores were estimated to measure the effect of BTX on pain reduction. For adverse events, the risk ratio for the incidence of side effects was calculated.

RESULTS

Two hundred and sixty non-duplicate articles were identified; however, only 14 RCTS were included in this review. The total study population included 395 patients. The overall risk of bias showed a low to moderate quality of evidence. Results from 6 studies were reported only narratively; four studies were used for meta-analysis on pain reduction, and five were used for meta-analysis on adverse events. The control used in the meta-analysis was placebo injections. Results of the meta-analysis for pain reduction were statistically insignificant for the BTX group with mean differences at MD = -1.71 (95% CI, -2.87 to -0.5) at one month, -1.53 (95% CI, -2.80 to -0.27) at three months, and -1.33 (95% CI, -2.74 to 0.77) at six months. This showed that BTX treatment was not significantly better than placebo for a reduction in pain scores at 1, 3, and 6 months. Regarding safety, the placebo group showed a relative risk of 1.34 (95%CI, 0.48-6.78) and 1.17 (95%CI, 0.54-3.88) at 1 and 3 months respectively. However, the risks were not statistically significant. There was also no difference in the effectiveness of BTX compared to placebo and other treatments for maximum mouth opening, bruxism events, and maximum occlusal force.

CONCLUSION

BTX was not associated with better outcomes in terms of pain reduction, adverse events, maximum mouth opening, bruxism events, and maximum occlusal force. More high-quality RCTs are needed to better understand this topic.

Psychological distress and the belief that oral behaviours put a strain on the masticatory system in relation to the self-report of awake bruxism: Four scenarios

BACKGROUND

It is assumed that other factors than masticatory muscle activity awareness could drive the self-report of awake bruxism.

OBJECTIVES

To investigate the extent to which the report of awake bruxism is associated with psychological distress, and with the belief that oral behaviours put a strain on the masticatory system among TMD-pain patients.

MATERIALS AND METHODS

The study sample consisted of 1830 adult patients with reported function-dependent TMD pain. Awake bruxism was assessed through six items of the Oral Behaviors Checklist. Psychological distress was assessed by means of somatic symptoms, depression and anxiety. Causal attribution belief was measured with the question 'Do you think these behaviours put a strain on your jaws, jaw muscles, and/or teeth?'

RESULTS

Mean age of all participants was 42.8 (±15.2) years, 78.2% being female. Controlled for sex, positive, yet weak, correlations were found between awake bruxism and somatic symptom severity (rs  = 0.258; p < .001), depression (rs  = 0.272; p < .001) and anxiety (rs  = 0.314; p < .001): patients with the highest scores reported approximately twice as much awake bruxism compared to those with minimal scores. Controlled for age and sex, a positive, moderate correlation was found between awake bruxism and causal attribution belief (rs  = 0.538; p < .001). Patients who believed that performing awake oral behaviours put 'very much' a strain on the masticatory system reported four times more awake bruxism than patients who did not believe that these behaviours are harmful.

CONCLUSIONS

Based on the results and relevant scientific literature, the theoretical background mechanisms of our findings are discussed in four scenarios that are either in favour of the use of self-report of awake bruxism being a representation of masticatory muscle activity awareness, or against it.

Effect of Botulinum Toxin on Masticatory Muscle Pain in Patients with Temporomandibular Disorders: A Randomized, Double-Blind, Placebo-Controlled Pilot Study

This study aimed to evaluate the efficacy of botulinum toxin type A (BoNT/A) in patients with temporomandibular disorders (TMDs) associated with masticatory muscle pain (MMP) and headaches. This randomized, double-blind, placebo-controlled pilot study is the first clinical trial to evaluate both disorders simultaneously. Twenty-one patients with myogenous TMD were randomly assigned to two groups. The experimental and control groups received injections of either BoNT/A or saline into the sites showing tenderness after palpation of a total of 16 muscle areas, including each masseter, a temporalis, splenius capitis, sternocleidomastoid, and trapezius muscle. During each visit, the clinical effects, based on the intensity of orofacial pain (OVAS), headache (HVAS), number of tender points (TPs), maximum mouth opening (MMO), and headache frequency (HF), were evaluated at four time points, namely, pre-injection and 4, 8, and 12 weeks after the injection, in both groups. Friedman and Mann-Whitney tests were used for the analyses. In the experimental group, the reductions in OVAS, TP, HVAS, and HF showed significant differences over time, excluding MMO, whereas there was no significant difference in any of the variables in the control group. In addition, the decline in TPs was significantly different between the experimental and control groups at all time points, especially after 4 and 12 weeks, compared to that during pre-injection. In conclusion, treatment with BoNT/A was relatively effective for masticatory muscle pain caused by TMDs and headache compared to the saline placebo.

Effects of a program consisting of strain/counterstrain technique, phonophoresis, heat therapy, and stretching in patients with temporomandibular joint dysfunction: A pilot study

BACKGROUND

The present study was conceptualized as a pilot study to examine the effects of a 3-week program consisting of strain/counterstrain technique (SCST), phonophoresis, heat therapy, and stretching exercises on pain and functions in patients with temporomandibular dysfunction (TMD).

METHODS

Seven participants (mean age 25.85 years) diagnosed with TMD having pain in the temporomandibular joint (TMJ) area with decreased jaw opening were recruited for the study. Treatment interventions consisting of SCST, phonophoresis (ultrasound gel mixed with diclofenac gel), heat therapy, and stretching (mouth-opening) exercises were performed 3 days a week for 3 weeks. SCST was performed on the masseter, medial, and lateral pterygoid muscles. No control group was present in the study.

RESULTS

Paired samples t test revealed a significant difference in numerical pain rating scale (NPRS) (decreased by 50%, P < .001) and jaw functional limitation scale (JFLS) (reduced by 59.58%, P < .001) scores after 3 weeks of intervention. A large effect size (Cohen d = -3.00 for NPRS and -3.16 for JFLS) was observed for both variables. No correlation (R = 0) was found between the baseline values of NPRS and JFLS.

CONCLUSION

A 3-week program consisting of SCST, phonophoresis, heat therapy, and stretching exercises was effective in reducing the pain and improving the functions related to TMJ in patients suffering from TMD. However, a randomized controlled trial is needed to reach a definite conclusion.

Role of Dynamic 3 Tesla MRI in the Evaluation of Temporomandibular Joint Dysfunction

INTRODUCTION

The internal derangement of the temporomandibular joint (TMJ) is the most common type of dysfunction. Internal derangement can be divided into anterior and posterior disc displacement. Anterior disc displacement is the most common type, which is further classified into anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR). Temporomandibular joint dysfunction (TMD) symptoms are pain, reduced mouth opening, and joint sound. The main aim of this study was to correlate the clinical findings and magnetic resonance imaging (MRI) diagnosis of TMD in symptomatic and asymptomatic TMJs.

METHODS

This prospective observational study was conducted in a tertiary care hospital on a 3T Philips Achieva MRI machine with 16-array channel coils after obtaining approval from the institutional ethical committee. A total of 60 TMJs of 30 patients were included in the study. After the clinical examination of each patient, an MRI of both right and left TMJs was done. In patients with unilateral TMD, the asymptomatic side was used as the asymptomatic joint, and the affected side as the symptomatic joint. Asymptomatic patients without any symptoms of TMD were used as controls for bilateral TMD cases. MRI with high-resolution specific serial sections was obtained in both open- and closed-mouth positions. A p-value of <0.05 was considered a statistically significant agreement between clinical and MRI diagnoses of internal derangement.

RESULTS

Out of a total of 30 clinically asymptomatic TMJs, only 23 were normal on MRI. On MRI, 26 TMJs showed ADDWR and 11 showed ADDWoR. The most common shape of the disc was biconcave and the displacement was anterior in symptomatic joints. The most common type of articular eminence shape was sigmoid in ADDWR and flattened in ADDWoR. Agreement between clinical and MRI diagnosis in this study was 87.5% (p < 0.001).

CONCLUSION

 The study concluded substantial agreement between clinical and MRI diagnosis of TMJ internal dysfunction and suggests that the diagnosis of the internal dysfunction can be made clinically but the exact position, shape, and type of disc displacement can be assessed precisely with the help of MRI.

The applications of cryoneurolysis for acute and chronic pain management

BACKGROUND

Cryoneurolysis is a term used to describe the application of extreme cold to targeted nerve tissue. The primary goal of the application of a thermal neurolytic technique is to disrupt the conduction of pain signals from the periphery to the central nervous system and eliminate or diminish the experience of pain. Recent advancements in ultrasound technology coupled with the development and approval of handheld devices specifically designed to deliver cryoneurolysis has expanded the use of this modality in the perioperative setting.

APPLICATION

Surgical procedures including total knee arthroplasties, shoulder arthroplasties, thoracotomies, and mastectomies have all demonstrated long-term pain relief benefits when cryoneurolysis has been administered days to weeks prior to the planned procedure. In addition, the newly designed handheld device allows for office-based clinical use and has been utilized for various chronic pain conditions including neuropathic and phantom limb pain.

CONCLUSION

The evidence clearly demonstrates that cryoneurolysis has a low risk profile and when administered appropriately, provides prolonged analgesia without promoting motor blockade. This narrative review article describes the unique mechanism of action of cryoneurolysis for prolonged pain relief and provides emerging evidence to support its applications in both acute and chronic pain management.

A novel rat model of temporomandibular disorder with improved face and construct validities

AIMS

Temporomandibular disorders are a cluster of orofacial conditions that are characterized by pain in the temporomandibular joint (TMJ) and surrounding muscles/tissues. Animal models of painful temporomandibular dysfunction (TMD) are valuable tools to investigate the mechanisms responsible for symptomatic temporomandibular joint and associated structures disorders. We tested the hypothesis that a predisposing and a precipitating factor are required to produce painful TMD in rats, using the ratgnawmeter, a device that determines temporomandibular pain based on the time taken for the rat to chew through two obstacles.

MATERIALS AND METHODS

Increased time in the ratgnawmeter correlated with nociceptive behaviors produced by TMJ injection of formalin (2.5%), confirming chewing time as an index of painful TMD. Rats exposed only to predisposing factors, carrageenan-induced TMJ inflammation or sustained inhibition of the catechol-O-methyltransferase (COMT) enzyme by OR-486, showed no changes in chewing time. However, when combined with a precipitating event, i.e., exaggerated mouth opening produced by daily 1-h jaw extension for 7 consecutive days, robust function impairment was produced.

KEY FINDINGS

These results validate the ratgnawmeter as an efficient method to evaluate functional TMD pain by evaluating chewing time, and this protocol as a model with face and construct validities to investigate symptomatic TMD mechanisms.

SIGNIFICANCE

This study suggests that a predisposition factor must be present in order for an insult to the temporomandibular system to produce painful dysfunction. The need for a combined contribution of these factors might explain why not all patients experiencing traumatic events, such as exaggerated mouth opening, develop TMDs.

Psychometric Evaluation of the Krogh-Poulsen Test for the Diagnosis of the Temporomandibular Disorders

The Krogh-Poulsen Test is a classic instrument to measure dysfunction of the stomatognathic system whose psychometric properties are unknown. This study aimed to evaluate the psychometric properties of the Krogh-Poulsen Test for the diagnosis of temporomandibular disorders (TMDs). A cross-sectional study was designed, including 119 patients (63 patients with TMD and 56 healthy controls). Factorial validity, inter-rater reliability, error of measurement, diagnostic validity of the Krogh-Poulsen Test, and concurrent validity were analyzed. The Krogh-Poulsen Test showed a three-factor structure. The inter-rater agreement could be considered very good with a kappa index of 0.87 (95% CI 0.83-0.90) and Standard Error of Measurement of 0.79. Correlations were strong with other orofacial instruments, moderate with instruments measuring TMD-related disorders such as neck pain, headache, or dizziness, and poor with generic quality of life instruments. The Area Under the Curve ROC was 0.928 showing, for a cut-off point >1, a sensitivity of 90.48 (95% CI 80.4-96.4) and a specificity of 85.71 (95% CI 73.8-93.6) for the diagnosis of TMD disorders. The Krogh-Poulsen Test showed a three-factor structure, very good inter-rater reliability, a strong correlation with other orofacial instruments, and an excellent capacity to discriminate between patients with or without TMD.

Reconstruction of the Anterior External Auditory Canal With Mastoid Cortex Autologous Bone Graft

OBJECTIVE

To describe the surgical management of temporomandibular joint (TMJ) herniation with external auditory canal (EAC) reconstruction using autologous bone grafting from the mastoid cortex.

STUDY DESIGN

Retrospective case series.

SETTING

A tertiary university medical center.

PATIENTS

Three patients who presented to our Otolaryngology clinic with evidence of TMJ herniation through an anterior EAC defect, both on otoscopy and computed tomography (CT) imaging.

INTERVENTIONS

Reconstruction of the anterior EAC with mastoid cortex bone grafting using an endaural approach.

MAIN OUTCOME MEASURES

Successful reconstruction of anterior EAC bony defect without recurrence of herniation.

RESULTS

All three patients presented with otalgia, hearing loss, and either tinnitus or a clicking sensation with jaw movement. Etiologies for TMJ herniation included osteoradionecrosis following external beam radiation therapy for head and neck carcinoma and iatrogenic injury following multiple tympanoplasties and canalplasties. A mastoid cortex bone graft was placed and secured anterior to the bony EAC defect through an endaural approach. Two patients wore a dental retainer postoperatively to keep the condyle in an open position. After reconstruction, patients reported an improvement in their presenting symptoms. There was no recurrence of TMJ herniation in all cases after 1, 4, and 9 years.

CONCLUSIONS

Anterior EAC reconstruction with autologous bone grafting can be an effective definitive treatment in TMJ herniation. To our knowledge, this is the first report of the use of bone grafting to reconstruct the canal defect in TMJ herniation.Level of Evidence: V.

Effectiveness of Acceptance and Commitment Therapy in Central Pain Sensitization Syndromes: A Systematic Review

OBJECTIVES

Acceptance and commitment therapy (ACT) is considered by the American Psychological Association as an evidence-based treatment for a variety of disorders, including chronic pain. The main objective of the present systematic review was to determine the effectiveness of ACT in patients with central pain sensitization syndromes (CPSS).

METHODS

This systematic review was conducted according to the guidelines of the Cochrane Collaboration and PRISMA statements. The protocol was registered in advance in the Prospective Register of Systematic Reviews (PROSPERO) international database. The selected articles were evaluated using the Cochrane risk of bias (ROB) assessment tool. The PubMed, Scopus, and Web of Science databases were searched.

RESULTS

The literature search identified 21 studies (including investigations of fibromyalgia syndrome, irritable bowel syndrome, and migraine) eligible for the systematic review. There were no studies regarding the effectiveness of ACT for chronic tension-type headache (CTTH), interstitial cystitis (IC), or temporomandibular disorder (TMD). The evaluation of ROB showed that 12 of the selected studies were of low quality, 5 were of moderate quality, and 4 were high quality. ACT reduces some clinical symptoms, such as anxiety, depression, and pain. This positive effect of ACT might be mediated by pain acceptance, psychological flexibility, optimism, self-efficacy, or adherence to values. ACT showed better results in comparison to non-intervention (e.g., "waiting list") conditions, as well as pharmacological and psychoeducational interventions. It is not entirely clear whether extended ACT treatments are more advantageous than briefer interventions.

CONCLUSIONS

There are few studies about the effectiveness of ACT on CPSS. However, ACT seems to reduce subjective CPSS symptoms and improve the health-related quality of life of these patients. The absence of studies on the effectiveness of ACT in CTTH, IC, and TMD, indicate the pressing need for further ACT studies in these CPSS.

Outcomes of temporomandibular joint disorders treatment after a survey in the population of Uttarakhand, Part I: An epidemiological study

Aim

To observe the prevalence of signs and symptoms of Temporomandibular joint disorders in patients visiting outpatient department, AIIMS Rishikesh.

Method and material

The survey was conducted in a total of 960 patients, who visited outpatient Department (OPD), dept of Dentistry, AIIMS Rishikesh and were asked to fill a questionnaire based on Fonseca questionnaire for TMD in accordance to the inclusion and exclusion criteria.

Results

Out of 960 patients, 449 had no TMD, 322 patients had mild TMD, 123 moderate and severe TMD was seen in 54 patients. Also, male dominance for TMD was seen in all the groups. There was no age predilection; however most of the patients with severe TMD fell between 16 and 60 years of age.

Conclusion

TMD is a common problem occurring in all age groups, there was a male dominance seen in the epidemiological study.

Botulinum toxin in the management of temporomandibular disorders: a systematic review

The aim of this review was to critically investigate and assess the evidence relating to the use and efficacy of botulinum toxin (BTX) in the management of temporomandibular joint disorders (TMD) and masticatory myofascial pain. A comprehensive search was conducted of PubMed, Scopus, Embase, and Cochrane CENTRAL, to find relevant studies from the last 30 years up to the end of July 2018. Seven were identified. Three showed a significant reduction in pain between the BTX and placebo groups and one showed a clinical, but not a significant, difference. In one that compared BTX with another novel treatment, myofascial pain reduced equally in both groups, and in the remaining two there was no significant difference in pain reduction between the BTX and control groups. Of the four studies that assessed mouth opening, two reported that BTX had resulted in a slight improvement; one reported no improvement, and the other a worsening of the condition. A meta-analysis was not possible because of the considerable variation in the studies' designs, the heterogeneity between the groups, and the different assessment tools used. Despite showing benefits, consensus on the therapeutic benefit of BTX in the management of myofascial TMD is lacking. Further randomised controlled trials with larger sample sizes, minimal bias, and longer follow-up periods are now needed.

Ankylosis of the Temporomandibular Joint in Pediatric Patients

INTRODUCTION

While surgical interventions for temporomandibular joint (TMJ) ankylosis are well-documented, there is lack of consensus regarding the ideal approach in pediatric patients. Surgical interventions include gap arthroplasty, interpositional arthroplasty, or total joint reconstruction.

METHODS

A systematic review of PubMed (Jan 1, 1990-Jan 1, 2017) and Scopus (Jan 1, 1990-Jan 1, 2017) was performed and included studies in English with at least one patient under the age of 18 diagnosed with TMJ ankylosis who underwent surgical correction. Primary outcomes of interest included surgical modality, preoperative maximum interincisal opening (MIO) (MIOpreop), postoperative MIO (MIOpostop), ΔMIO (ΔMIO = MIOpostop - MIOpreop), and complications.

RESULTS

Twenty-four case series/reports with 176 patients and 227 joints were included. By independent sample t tests MIOpostop (mm) was greater for gap arthroplasty (30.18) compared to reconstruction (27.47) (t = 4.9, P = 0.043), interpositional arthroplasty (32.87) compared to reconstruction (t = 3.25, P = 0.002), but not for gap compared to interpositional (t = -1.9, P = 0.054). ΔMIO (mm) was greater for gap arthroplasty (28.67) compared to reconstruction (22.24) (t = 4.2, P = 0.001), interpositional arthroplasty (28.33) compared to reconstruction (t = 3.27, P = 0.002), but not for interpositional compared to gap (t = 0.29, P = 0.33). Weighted-average follow-up time was 28.37 months (N = 164). 4 of 176 (2.27%) patients reported development of re-ankylosis. There was no significant difference in occurrence of re-ankylosis between interventions.

CONCLUSIONS

Given the technical ease of gap arthroplasty and nonsignificant differences in ΔMIO, MIOpostop, or occurrence of re-ankylosis between gap and interpositional arthroplasty, gap arthroplasty should be considered for primary ankylosis repair in pediatric patients, with emphasis on postoperative physiotherapy to prevent recurrent-ankylosis.

Association Between Tinnitus and Temporomandibular Disorders: A Systematic Review and Meta-Analysis

OBJECTIVES

Tinnitus is one of the most common otological symptoms in patients with temporomandibular disorders. This study aimed to investigate the possible association between tinnitus and temporomandibular disorders.

METHODS

The online databases of PubMed, Ovid, ScienceDirect, and Web of Science were explored for all English articles published until September 2018 using the combined keywords tinnitus and temporomandibular. Cross-sectional, cohort, or case-control studies that investigated the association between tinnitus and temporomandibular disorders (TMDs) were considered. The quality of the included papers was assessed by the Crowe Critical Appraisal Tool.

RESULTS

Twenty-two papers met the eligibility criteria and were included in the systematic review. Meta-analysis was performed on 8 papers to investigate the possible relationship between tinnitus and TMDs by calculating the odds ratios. Odds ratios ranged from 1.78 to 7.79 in the studies related to tinnitus frequency in temporomandibular disorders and from 1.80 to 7.79 in the papers linked to temporomandibular disorder frequency in tinnitus, indicating a significant association between tinnitus and temporomandibular disorders.

CONCLUSIONS

There was a strong relationship between tinnitus occurrence and TMDs. The findings implied the significance of exploring the signs of TMDs in patients with tinnitus as well as tinnitus in those who complain from temporomandibular disorders.

Advancements in temporomandibular joint total joint replacements (TMJR)

The goal of this paper is to review the advantages and disadvantages of the various treatment options of temporomandibular joint (TMJ) total joint replacement (TJR). TMJ articles published within the last 20 years were reviewed to collect the information on non-invasive and invasive TMD treatment methods. Recent technological advancements helped the evolution of treatment methods and offered significant value to TMD patients and surgeons. Considering the TMD levels, the therapeutic procedures can involve general health examiniations, physical therapy, medication, oral rehabilation or as an end stage clinical invention, temporomandibular joint replacement. In fact when intra-articular TMD is present, the effective treatment method appears to be TJR. However, concern for infection, material hypersensitivity, device longevity and screws loosening issues still exists. Further combined research utilizing the knowledge and expertise of, surgeons, material scientists, and bioengineers is needed for the development of improved TMD therapeutic treatment.

Comparison between intra-articular platelet-rich plasma injection versus hydrocortisone with local anesthetic injections in temporomandibular disorders: A double-blind study

Introduction:

Temperomandibular joint (TMJ) is subjected to many disorders commonly called Temperomandibular disorders (TMDs); such as TMJ hypermobility, ankylosis, internal derangement, degenerative joint disease. Internal derangement is characterized by abnormal relationship of articular disc to the condyle and disc to fossa. In past many non-invasive conservative treatment modalities were tried out for its treatment which are joint unloading, use of anti-inflammatory agents, physiotherapy etc. Now a days corticosteroids and platelet rich plasma (PRP) has been proposed as an alternative therapeutic agent. We aimed to assess whether intra articular injection of PRP in TMJ minimises the symptoms of internal derangements as compared to injection of hydrocortisone with local anaesthetic.

Materials and Methods:

Twenty patients for a total of 32 joints with reducible anterior disc location were divided in two groups. One group received PRP injection and the other received hydrocortisone with local anaesthetic for arthroscopy in their affected joints. Both patients and operator were blinded to the contents of injections. The patients were assessed for pain, maximum inter-incisal mouth opening and TMJ sound.

Results:

In the group of PRP injection, pain was markedly reduced than the group of hydrocortisone with local anesthetic; mouth opening was increased similarly in both groups and TMJ sound was experienced lesser in patients who received PRP.

Conclusion:

Injections of PRP were more effective in reducing the symptoms, as compared to hydrocortisone with local anaesthetics.

Therapeutic Evaluation of Cervical Dysfunction in Patients with Myofascial Pain Dysfunction Syndrome: A Prospective Study

AIM

The aim of this study was to find out the therapeutic correlation between cervical dysfunction and myofascial pain dysfunction syndrome (MPDS).

MATERIALS AND METHODS

The study included 46 patients out of which 23 had MPDS with cervical pain (group I), and 23 patients had only MPDS (group II). Detailed history and examination of the patients were carried out, and the factors taken into consideration were pain and tenderness of muscles of mastication and neck muscles, maximum comfortable mouth opening, and cervical range of motion. All the patients were randomly divided and advised physical exercises, light amplification by stimulated emission of radiation (LASER) therapy, and the combination of both exercise and LASER. Patients were assessed for the relief of signs and symptoms of myofascial pain and cervical pain posttreatment, every month for 2 months.

RESULTS

Both the groups showed a similar response to all the different treatment modalities. In group I, the patients also had relief in their cervical pain although the treatment was directed for MPDS. Patients from both the groups who were advised LASER and combination of both exercise and LASER showed better response in terms of reduction in visual analog scale, number of tender muscles, and increased maximum comfortable mouth opening posttreatment and during the follow-up, as compared with the patients who were advised only exercise.

CONCLUSION

Patients having cervical pain showed significant improvement comparable with patients having no cervical pain. Hence, the conclusion drawn was that there is a positive interrelationship between MPDS and cervical (neck) pain; MPDS may act as a catalyst for precipitating cervical pain.

CLINICAL SIGNIFICANCE

Cervical pain showed significant improvement to physiotherapy in the form of exercise, LASER, and combination treatment, though the effective modality was LASER and combination of exercise and LASER therapy.

Effectiveness of two different splints to treat temporomandibular disorders

Nearly 5% of the the world's population has temporomandibular disorder (TMD) severe enough to make them seek treatment. A third of the total population has at least one TMD symptom. There are different types of splints to treat TMD. In our study, we compared the success of two different appliances [stabilization splint (ss), nociceptive trigeminal inhibition splint (NTI)] by using Fonseca's questionnaire, the OHQoL-UK and visual analog scale (VAS). A total of 40 patients suffering from TMD were included in this study and answered questionnaires twice, at the beginning of the treatment and 3 months later. Regarding TMD alone, 39 patients (97.5%) had some degree of the disorder, 7 of of these cases being mild (17.5%), 15 moderate (37.5%), and 17 severe (42.5%). We analyzed posttreatment changes compared to baseline. Pain complaints decreased in both groups, and the OHQoL-UK revealed better quality of life after treatment. Based on the posttreatment Fonseca's questionnaires, significant changes in the patients' complaints in the group SS (p < 0.01) were observed. The group NTI also displayed changes but these were not statistically significant after treatment (p > 0.05). Patients in both groups had fewer TMD complaints after TMJ treatment. According to the Fonseca's questionnaire, the patients' major TMD complaint was clenching-grinding, followed by pain in the craniomandibular joint, or earache.

Association of pain intensity, pain-related disability, and depression with hypothalamus-pituitary-adrenal axis function in female patients with chronic temporomandibular disorders

Patients with temporomandibular disorders (TMD) commonly experience myofascial and joint pain, pain-related disability, and other pain conditions including depression. The present study was carried out to explore the function of the hypothalamus-pituitary-adrenal (HPA) axis in relation to variables of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II and comorbid depression in female patients with TMD. Cortisol and dehydroepiandrosterone (DHEA) levels were determined in saliva samples that had been collected at various periods after waking (0, 30, and 60min) and at nighttime (2100-2200h) from 52 female patients with chronic TMD pain and age- and gender-matched controls (n=54, 20-40 years old). There were no significant differences in the levels and diurnal patterns of cortisol and DHEA secretion between groups of patients with TMD and controls. In patients, the cortisol awakening response (CAR) or diurnal cortisol rhythm were not associated with any variables of the RDC/TMD Axis II or the Beck Depression Inventory (BDI)-II total scores. However, the ratio of overall cortisol secretion within the first hour after waking (CARauc) to overall DHEA secretion during the post-waking period (Daucawk), defined as CARauc/Daucawk, was significantly associated with pain-related RDC/TMD variables (pain intensity and pain-related disability) and BDI-II total scores. Pain intensity and pain-related disability scores were also significantly associated with BDI-II total scores. These results indicated that an increase in molar cortisol/DHEA ratio due to the dissociation between cortisol and DHEA secretion was associated with pain intensity, pain-related disability, and depression in female patients with TMD.

Upregulation of lncRNA HOTAIR contributes to IL-1β-induced MMP overexpression and chondrocytes apoptosis in temporomandibular joint osteoarthritis

Temporomandibular joint osteoarthritis (TMJ OA) is a common and heterogeneous disease that causes painful and progressive joint degeneration, which restricts daily activities, including talking and chewing. Long noncoding RNAs (lncRNAs) are an important class of genes involved in various physiological and pathological functions, including osteoarthritis (OA).The present study aimed to identify the lncRNAs that are important in TMJ OA and their potential functions. Here, we found that HOTAIR was significantly upregulated in the synovial fluid of TMJ OA patients compared with that of normal controls. Increased HOTAIR was similarly observed in the synovial fluid of TMJ OA rabbits as compared to control rabbits. Furthermore, in interleukin-1β (IL-1β)-induced TMJ OA in vitro model (primary rabbit condylar chondrocytes), the expressions of matrix metalloproteinase (MMP)-1, MMP3, MMP9 and HOTAIR were all dramatically increased. Most importantly, knockdown of HOTAIR in IL-1β-induced TMJ OA in vitro model could not only reverse the IL-1β-stimulated expressions of MMP1, MMP3 and MMP9, but also significantly decrease the apoptosis rate induced by IL-1β in primary rabbit condylar chondrocytes. Our data provides new insight into the mechanisms of chondrocytes destruction in TMJ OA.

Oral toxicity management in head and neck cancer patients treated with chemotherapy and radiation: Xerostomia and trismus (Part 2). Literature review and consensus statement

Radiotherapy alone or in combination with chemotherapy and/or surgery is a well-known radical treatment for head and neck cancer patients. Nevertheless acute side effects (such as moist desquamation, skin erythema, loss of taste, mucositis etc.) and in particular late toxicities (osteoradionecrosis, xerostomia, trismus, radiation caries etc.) are often debilitating and underestimated. A multidisciplinary group of head and neck cancer specialists from Italy met in Milan with the aim of reaching a consensus on a clinical definition and management of these toxicities. The Delphi Appropriateness method was used for this consensus and external experts evaluated the conclusions. The paper contains 20 clusters of statements about the clinical definition and management of stomatological issues that reached consensus, and offers a review of the literature about these topics. The review was split into two parts: the first part dealt with dental pathologies and osteo-radionecrosis (10 clusters of statements), whereas this second part deals with trismus and xerostomia (10 clusters of statements).

Assessment of functional improvement with temporalis myofascial flap after condylectomy in elderly patients with anterior disc displacement without reduction and an erosive condylar surface

Background

The purpose of this study was to investigate the functional effects of temporalis myofascial flap after condylectomy, with or without disc removal, in elderly patients with anterior disc displacement (ADD) without reduction and an erosive condylar surface of the temporomandibular joint (TMJ).

Methods

A total of 15 joints from 11 elderly patients (71–78 years old) were included. The patients had pain, mandibular dysfunction symptoms, and unilateral or bilateral ADD as well as an erosive condylar surface of the TMJ. All patients underwent temporalis myofascial flap reconstruction after condylectomy, with or without disc removal. If the maximal mouth opening (MMO) remained <35 mm after condylectomy, coronoidotomy was also performed. Self-assessed pain and mandibular function, including MMO and protrusive and lateral movements, were evaluated.

Results

No patient experienced serious complications. Most measurements improved significantly after surgery compared to preoperatively. Most patients achieved nearly-normal mouth opening at 4 weeks after surgery. Although most patients felt discomfort during active postoperative physiotherapy, no patient reported serious pain during the follow-up period.

Conclusion

Although nonsurgical therapy is often the first treatment choice for ADD without reduction of the TMJ, surgical intervention involving condylectomy and temporalis myofascial flap reconstruction may be a reasonable first option for elderly patients with an erosive condylar surface of the TMJ.

Correlation Between Clinical Findings of Temporomandibular Disorders and MRI Characteristics of Disc Displacement

Objectives : Temporomandibular joint (TMJ) dysfunction is a common condition that is best evaluated with magnetic resonance (MR) imaging. The first step in MR imaging of the TMJ is to evaluate the articular disk, or meniscus, in terms of its morphologic features and its location relative to the condyle in both closed- and open-mouth positions. Disk location is of prime importance because the presence of a displaced disk is a critical sign of TMJ dysfunction. However, disk displacement is also frequently seen in asymptomatic volunteers. It is important for the maxillofacial radiologist to detect early MR imaging signs of dysfunction, thereby avoiding the evolution of this condition to its advanced and irreversible phase which is characterized by osteoarthritic changes such as condylar flattening or osteophytes. Further the MR imaging techniques will allow a better understanding of the sources of TMJ pain and of any discrepancy between imaging findings and patient symptoms. Henceforth, the aim of the study was to evaluate whether MRI findings of various degrees of disk displacement could be correlated with the presence or absence of clinical signs and symptoms of temporomandibular disorders in symptomatic and asymptomatic subjects. Materials and Methods : In this clinical study, 44 patients (88 TMJs) were examined clinically and divided into two groups. Group 1 consisted of 22 patients with clinical signs and symptoms of TMDs either unilaterally or bilaterally and considered as study group. Group 2 consisted of 22 patients with no signs and symptoms of TMDs and considered as control group. MRI was done for both the TMJs of each patient. Displacement of the posterior band of articular disc in relation to the condyle was quantified as anterior disc displacement with reduction (ADDR), anterior disc displacement without reduction (ADDWR), posterior disc displacement (PDD). Results : Disk displacement was found in 18 (81.8%) patients of 22 symptomatic subjects in Group 1 on MRI and 4 (18.1%) were diagnosed normal with no disc displacement. In Group 2, 2 (9.1%) of 22 asymptomatic patients were diagnosed with disc displacement while 20 (90.1%) were normal. Sensitivity and Specificity tests were applied in both the groups to correlate clinical findings of TMD and MRI characterstics of disc displacement and results showed Sensitivity of 90% and Specificity of 83.3%. Conclusion : Disk displacement on MRI correlated well with presence or absence of clinical signs and symptoms of temporomandibular disorders with high Sensitivity and Specificity of 90% and 83.3% respectively.

Botulinum toxin in the treatment of muscle specific Oro-facial pain: a literature review

Facial pain associated with temporomandibular joint (TMJ) and surrounding structures has been a challenge to clinicians as far as diagnosis and management is concerned. Complexity of anatomical structures within a small area, function of teeth and surrounding periodontal ligament, action of muscles, pathologies, lack of diagnostic investigations, all these complicate specific diagnosis of TMJ disorders. Various classifications have been designed and studied to help diagnose and treat TMJ related disorders, of which the simplest one is pain from TMJ proper and surrounding muscles. Many treatment modalities to treat pain arising from muscles around TMJ like splints, mouth restriction exercises, injection of sclerosing agents etc. have been used with various degrees of success. Botulinum toxin has been shown to be effective in the treatment of oro-facial pain due to muscular disorders and the same is discussed in detail in this review literature.

Assessment of condylar changes in patients with temporomandibular joint pain using digital volumetric tomography

Objective. To evaluate the efficiency of DVT in comparison with OPG in the assessment of bony condylar changes in patients of TMJ pain. Methods. 100 temporomandibular joints of 62 patients with the complaint of temporomandibular joint pain were included in the study. DVT and OPG radiographs were taken for all the 100 joints. Three observers interpreted the DVT and OPG radiograph for the bony changes separately for two times with an interval of one week. The bony changes seen in the condyle were given coding from 0 to 6. (0: Normal, 1: Erosion, 2: Flattening, 3: Osteophyte, 4: Sclerosis, 5: Resorption, and 6: other changes). Interobserver and intraobserver variability was assessed with one-way ANOVA statistics. Z test was used to see the significant difference between OPG and DVT. Results. In the present study the interexaminer reliability for OPG and DVT was 0.903 and 0.978, respectively. Intraexaminer reliability for OPG and DVT was 0.908 and 0.980, respectively. The most common condylar bony change seen in OPG and DVT was erosion followed by flattening and osteophyte. There was significant difference between OPG and DVT in detecting erosion and osteophytes. The other changes observed in our study were Ely's cyst, pointed condyle, and bifid condyle. All the bony changes are more commonly seen in females than males. Conclusion. DVT provides more valid and accurate information on condylar bony changes. The DVT has an added advantage of lesser radiation exposure to the patient and cost effectiveness and could be easily accessible in a dental hospital.

Dual orexin receptor antagonist 12 inhibits expression of proteins in neurons and glia implicated in peripheral and central sensitization

Sensitization and activation of trigeminal nociceptors is implicated in prevalent and debilitating orofacial pain conditions including temporomandibular joint (TMJ) disorders. Orexins are excitatory neuropeptides that function to regulate many physiological processes and are reported to modulate nociception. To determine the role of orexins in an inflammatory model of trigeminal activation, the effects of a dual orexin receptor antagonist (DORA-12) on levels of proteins that promote peripheral and central sensitization and changes in nocifensive responses were investigated. In adult male Sprague-Dawley rats, mRNA for orexin receptor 1 (OX₁R) and receptor 2 (OX₂R) were detected in trigeminal ganglia and spinal trigeminal nucleus (STN). OX₁R immunoreactivity was localized primarily in neuronal cell bodies in the V3 region of the ganglion and in laminas I-II of the STN. Animals injected bilaterally with complete Freund's adjuvant (CFA) in the TMJ capsule exhibited increased expression of P-p38, P-ERK, and lba1 in trigeminal ganglia and P-ERK and lba1 in the STN at 2 days post injection. However, levels of each of these proteins in rats receiving daily oral DORA-12 were inhibited to near basal levels. Similarly, administration of DORA-12 on days 3 and 4 post CFA injection in the TMJ effectively inhibited the prolonged stimulated expression of protein kinase A, NFkB, and Iba1 in the STN on day 5 post injection. While injection of CFA mediated a nocifensive response to mechanical stimulation of the orofacial region at 2h and 3 and 5 days post injection, treatment with DORA-12 suppressed the nocifensive response on day 5. Somewhat surprisingly, nocifensive responses were again observed on day 10 post CFA stimulation in the absence of daily DORA-12 administration. Our results provide evidence that DORA-12 can inhibit CFA-induced stimulation of trigeminal sensory neurons by inhibiting expression of proteins associated with sensitization of peripheral and central neurons and nociception.

Treatment of myogenic temporomandibular disorder: a prospective randomized clinical trial, comparing a mechanical stretching device (TheraBite®) with standard physical therapy exercise

AIMS

To compare in a randomized controlled clinical trial (RCT) the application of the TheraBite® (TB) Jaw Motion Rehabilitation System with a standard physical therapy (PT) exercise regimen for the treatment of myogenic temporomandibular disorder (TMD).

METHODOLOGY

Myogenic TMD patients were randomized for the use of the TB device or for standard PT. Mandibular function was assessed with the mandibular function impairment questionnaire (MFIQ). Pain was evaluated using a visual analog scale, and maximum inter-incisor (mouth) opening (MIO) was measured using the disposable TB range of motion scale.

RESULTS

Of the 96 patients randomized (46 TB, 50 standard PT exercises), 38 actually started with the TB device and 41 with the standard PT exercises. After six-week follow-up, patients using the TB device reported a significantly greater functional improvement (MFIQ score) than the patients receiving regular PT exercises (P = 0.0050). At 6 weeks, no significant differences in pain, and active or passive MIO were found between the two groups. At 3 months, patients in both treatment groups did equally well, and showed a significant improvement in all parameters assessed.

CONCLUSIONS

This RCT on myogenic TMD treatment, comparing standard PT with passive jaw mobilization using the TheraBite Jaw Motion Rehabilitation System®, shows that both treatment modalities are equally effective in relieving myogenic TMD symptoms, but that the use of the TB device has the benefit of achieving a significantly greater functional improvement within the first week of treatment.

Occlusal stability

Occlusion is the foundation for clinical success in fixed, removable, and implant prosthodontic treatment. Understanding those principles is critical when restoring a patient's occlusion. Many philosophies, devices, and theories of occlusion have evolved based on anecdotal clinical observations and applied geometric perceptions. The literature has reported these classic and contemporary occlusal concepts. As evidence-based dentistry emerged, it championed scrutiny of previously held beliefs, resulting in the abandonment of many pragmatic, yet beneficial occlusal procedures. The impetus toward scientific discovery, whereby factual information might be universally applied in dental education and clinical practice, has renewed interest in occlusal studies.

Mandibular asymmetry: a three-dimensional quantification of bilateral condyles

INTRODUCTION

The shape and volume of the condyle is considered to play an important role in the pathogenesis of the mandibular deviation. Curvature analysis is informative for objectively assess whether the shape of the condyles matches that of the glenoid fossa. In this study, a three-dimensional (3-D) quantification of bilateral asymmetrical condyles was firstly conducted to identify the specific role of 3-D condylar configuration for mandibular asymmetry.

METHODS

55 adult patients, 26 males (26 ± 5 yrs) and 29 females (26 ± 5 yrs), diagnosed with mandibular asymmetry were included. The examination of deviation of chin point, deviation of dental midlines, inclination of occlusal plane, and depth of the mandibular occlusal plane were conducted. After the clinical investigation, computed tomography images from the patients were used to reconstruct the 3-D mandibular models. Then the condylar volume, surface size, surface curvature and bone mineral density were evaluated independently for each patient on non-deviated and deviated sides of temporomandibular joint.

RESULTS

Both the condylar surface size and volume were significantly larger on deviated side (surface size: 1666.14 ± 318.3 mm2, volume: 1981.5 ± 418.3 mm3). The anterior slope of the condyle was flatter (0.12 ± 0.06) and the posterior slope (0.39 ± 0.08) was prominently convex on the deviated side. The corresponding bone mineral density values were 523.01 ±118.1 HU and 549.07 ±120. 6 HU on anterior and posterior slopes.

CONCLUSIONS

The incongruence presented on the deviated side resulted in a reduction in contact areas and, thus, an increase in contact stresses and changes of bone density. All aforementioned results suggest that the difference existing between deviated and non-deviated condyles correlates with facial asymmetrical development. In mandibular asymmetry patients, the 3-D morphology of condyle on deviated side differ from the non-deviated side, which indicates the association between asymmetrical jaw function and joint remodeling.

Inclusion of cocoa as a dietary supplement represses expression of inflammatory proteins in spinal trigeminal nucleus in response to chronic trigeminal nerve stimulation

SCOPE

Central sensitization is implicated in the pathology of temporomandibular joint disorder and other types of orofacial pain. We investigated the effects of dietary cocoa on expression of proteins involved in the development of central sensitization in the spinal trigeminal nucleus (STN) in response to inflammatory stimulation of trigeminal nerves.

METHODS AND RESULTS

Male Sprague-Dawley rats were fed either a control diet or an isocaloric diet consisting of 10% cocoa powder 14 days prior to bilateral injection of complete Freund's adjuvant (CFA) into the temporomandibular joint to promote prolonged activation of trigeminal ganglion neurons and glia. While dietary cocoa stimulated basal expression of glutamate-aspartate transporter and mitogen-activated protein kinase phosphatase-1 when compared to animals on a normal diet, cocoa suppressed basal calcitonin gene-related peptide levels in the STN. CFA-stimulated levels of protein kinase A, P2X3 , P-p38, glial fibrillary-associated protein, and OX-42, whose elevated levels in the STN are implicated in central sensitization, were repressed to near control levels in animals on a cocoa-enriched diet. Similarly, dietary cocoa repressed CFA-stimulated inflammatory cytokine expression.

CONCLUSION

Based on our findings, we speculate that cocoa-enriched diets could be beneficial as a natural therapeutic option for temporomandibular joint disorder and other chronic orofacial pain conditions.

Phenotypic alterations of neuropeptide Y and calcitonin gene-related peptide-containing neurons innervating the rat temporomandibular joint during carrageenan-induced arthritis

The aim of this study was to identify immunoreactive neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) neurons in the autonomic and sensory ganglia, specifically neurons that innervate the rat temporomandibular joint (TMJ). A possible variation between the percentages of these neurons in acute and chronic phases of carrageenan-induced arthritis was examined. Retrograde neuronal tracing was combined with indirect immunofluorescence to identify NPY-immunoreactive (NPY-IR) and CGRP- immunoreactive (CGRP-IR) neurons that send nerve fibers to the normal and arthritic temporomandibular joint. In normal joints, NPY-IR neurons constitute 78±3%, 77±6% and 10±4% of double-labeled nucleated neuronal profile originated from the superior cervical, stellate and otic ganglia, respectively. These percentages in the sympathetic ganglia were significantly decreased in acute (58±2% for superior cervical ganglion and 58±8% for stellate ganglion) and chronic (60±2% for superior cervical ganglion and 59±15% for stellate ganglion) phases of arthritis, while in the otic ganglion these percentages were significantly increased to 19±5% and 13±3%, respectively. In the trigeminal ganglion, CGRP-IR neurons innervating the joint significantly increased from 31±3% in normal animals to 54±2% and 49±3% in the acute and chronic phases of arthritis, respectively. It can be concluded that NPY neurons that send nerve fibers to the rat temporomandibular joint are located mainly in the superior cervical, stellate and otic ganglia. Acute and chronic phases of carrageenan-induced arthritis lead to an increase in the percentage of NPY-IR parasympathetic and CGRP-IR sensory neurons and to a decrease in the percentage of NPY-IR sympathetic neurons related to TMJ innervation.

Protection of articular cartilage by intra-articular injection of NEL-like molecule 1 in temporomandibular joint osteoarthritis

Several studies have proven the ability of NEL-like molecule-1 (Nell-1) to induce chondrogenesis and make it as a potential candidate for articular cartilage repair. In the current study, the chondroprotective effect of Nell-1 on osteoarthritis (OA) of the temporomandibular joint (TMJ) was investigated by intra-articular injection. Bilateral partial discectomy was performed in 24 rabbits to induce TMJOA. Four weeks later, the right TMJ was treated with Nell-1 as the experimental group, whereas the left was treated with physiologic saline as the control group. Twelve rabbits each time were randomly killed at 12 and 24 weeks after injection, respectively. Histologic observation and metabolic analysis by reverse transcription-polymerase chain reaction were used for evaluation. All TMJs appeared as OA-like histologic changes after intra-articular injection. However, the degree of osteoarthritis in the experimental group was less severe than that in the control group during the experimental time. The expression of type II collagen and aggrecan messenger RNA was significantly higher than the control group at 12 weeks after injection. However, no difference in the expression of aggrecanase or interleukin 1 messenger RNA was observed. The results suggest that intra-articular injection of Nell-1 may be a good alternative for the treatment of cartilage degeneration in OA.

Antinociceptive and anti-inflammatory effects of electroacupuncture on experimental arthritis of the rat temporomandibular joint

This study investigated the antinociceptive and anti-inflammatory effects of electroacupuncture (EA) on zymosan-induced acute arthritis of the rat temporomandibular joint (TMJ). Male Wistar rats were injected with saline or zymosan (control group; 2 mg) into the left TMJ. Low frequency EA (10 Hz, 30 min) was performed at acupoints (LI4, LI11, ST36, ST44) or sham points 2 h after or 1 h before zymosan administration. Mechanical hypernociception was accessed by the electronic Von Frey method after zymosan administration. Rats were sacrificed 6 h after zymosan administration and the joint was removed for histopathological analysis, myeloperoxidase activity assessment, vascular permeability observations, and immunohistochemical verification of inflammatory mediators. The results showed that EA inhibited zymosan-induced hypernociception, compared with the control group and with the sham group (p < 0.05). The results showed that EA inhibited inflammatory parameters such as neutrophil migration, vascular permeability, and tumour necrosis factor α (TNF-α), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) expression in the TMJ compared with the sham group (p < 0.05). Histopathological analysis showed that EA significantly inhibited edema and periarticular infiltration (p < 0.05) compared with the control and sham groups. EA at acupoints produced antinociceptive and anti-inflammatory effects on zymosan-induced arthritis in the rat TMJ.

Dietary grape seed polyphenols repress neuron and glia activation in trigeminal ganglion and trigeminal nucleus caudalis

BACKGROUND

Inflammation and pain associated with temporomandibular joint disorder, a chronic disease that affects 15% of the adult population, involves activation of trigeminal ganglion nerves and development of peripheral and central sensitization. Natural products represent an underutilized resource in the pursuit of safe and effective ways to treat chronic inflammatory diseases. The goal of this study was to investigate effects of grape seed extract on neurons and glia in trigeminal ganglia and trigeminal nucleus caudalis in response to persistent temporomandibular joint inflammation. Sprague Dawley rats were pretreated with 200 mg/kg/d MegaNatural-BP grape seed extract for 14 days prior to bilateral injections of complete Freund's adjuvant into the temporomandibular joint capsule.

RESULTS

In response to grape seed extract, basal expression of mitogen-activated protein kinase phosphatase 1 was elevated in neurons and glia in trigeminal ganglia and trigeminal nucleus caudalis, and expression of the glutamate aspartate transporter was increased in spinal glia. Rats on a normal diet injected with adjuvant exhibited greater basal levels of phosphorylated-p38 in trigeminal ganglia neurons and spinal neurons and microglia. Similarly, immunoreactive levels of OX-42 in microglia and glial fibrillary acidic protein in astrocytes were greatly increased in response to adjuvant. However, adjuvant-stimulated levels of phosphorylated-p38, OX-42, and glial fibrillary acidic protein were significantly repressed in extract treated animals. Furthermore, grape seed extract suppressed basal expression of the neuropeptide calcitonin gene-related peptide in spinal neurons.

CONCLUSIONS

Results from our study provide evidence that grape seed extract may be beneficial as a natural therapeutic option for temporomandibular joint disorders by suppressing development of peripheral and central sensitization.

Measurement of the Curve of Spee in horses

The Curve of Spee is well known, yet hardly understood in the horse, as there is a striking lack of biometrically related data which could help to explain its biomechanical significance. Older horses display drastic alterations of the Curve of Spee in routine clinical examinations. Since the Curve of Spee is known to be biomechanically related to the masticatory forces in humans, the same may apply to the equine, and masticatory deficits can be expected in the geriatric horse. Quantitative data of the Curve of Spee cannot be obtained directly by means of measurements in the horse's long and narrow oral cavity. Instead, the radiographs of 24 heads and 6 skulls of horses of different age were used to develop a geometrical procedure facilitating a quantitative analysis of the height of the Curve of Spee. The geometrical values gave clear evidence that the height of the Curve of Spee was smaller in groups of older horses compared with those of younger horses. This finding was in accordance with biomechanical studies which reported decreased masticatory forces in older horses.

Cocoa-enriched diets enhance expression of phosphatases and decrease expression of inflammatory molecules in trigeminal ganglion neurons

Activation of trigeminal nerves and release of neuropeptides that promote inflammation are implicated in the underlying pathology of migraine and temporomandibular joint (TMJ) disorders. The overall response of trigeminal nerves to peripheral inflammatory stimuli involves a balance between enzymes that promote inflammation, kinases, and those that restore homeostasis, phosphatases. The goal of this study was to determine the effects of a cocoa-enriched diet on the expression of key inflammatory proteins in trigeminal ganglion neurons under basal and inflammatory conditions. Rats were fed a control diet or an isocaloric diet enriched in cocoa for 14days prior to an injection of noxious stimuli to cause acute or chronic excitation of trigeminal neurons. In animals fed a cocoa-enriched diet, basal levels of the mitogen-activated kinase (MAP) phosphatases MKP-1 and MKP-3 were elevated in neurons. Importantly, the stimulatory effects of acute or chronic peripheral inflammation on neuronal expression of the MAPK p38 and extracellular signal-regulated kinases (ERK) were significantly repressed in response to cocoa. Similarly, dietary cocoa significantly suppressed basal neuronal expression of calcitonin gene-related peptide (CGRP) as well as stimulated levels of the inducible form of nitric oxide synthase (iNOS), proteins implicated in the underlying pathology of migraine and TMJ disorders. To our knowledge, this is the first evidence that a dietary supplement can cause upregulation of MKP, and that cocoa can prevent inflammatory responses in trigeminal ganglion neurons. Furthermore, our data provide evidence that cocoa contains biologically active compounds that would be beneficial in the treatment of migraine and TMJ disorders.

Nitric oxide-proton stimulation of trigeminal ganglion neurons increases mitogen-activated protein kinase and phosphatase expression in neurons and satellite glial cells

Elevated nitric oxide (NO) and proton levels in synovial fluid are implicated in joint pathology. However, signaling pathways stimulated by these molecules that mediate inflammation and pain in the temporomandibular joint (TMJ) have not been investigated. The goal of this study was to determine the effect of NO-proton stimulation of rat trigeminal neurons on the in vivo expression of mitogen-activated protein kinases (MAPKs) and phosphatases (MKPs) in trigeminal ganglion neurons and satellite glial cells. Low levels of the active MAPKs extracellular signal-regulated kinase (ERK), Jun amino-terminal kinase (JNK), and p38 were localized in the cytosol of neurons and satellite glial cells in unstimulated animals. However, increased levels of active ERK and p38, but not JNK, were detected in the cytosol and nucleus of V3 neurons and satellite glial cells 15 min and 2 h following bilateral TMJ injections of an NO donor diluted in pH 5.5 medium. While ERK levels returned to near basal levels 24 h after stimulation, p38 levels remained significantly elevated. In contrast to MKP-2 and MKP-3 levels that were barely detectable in neurons or satellite glial cells, MKP-1 staining was readily observed in satellite glial cells in ganglia from unstimulated animals. However, neuronal and satellite glial cell staining for MKP-1, MKP-2, and MKP-3 was significantly increased in response to NO-protons. Increased active ERK and p38 levels as well as elevated MKP levels were also detected in neurons and satellite glial cells located in V2 and V1 regions of the ganglion. Our data provide evidence that NO-proton stimulation of V3 neurons results in temporal and spatial changes in expression of active ERK and p38 and MKPs in all regions of the ganglion. We propose that in trigeminal ganglia these cellular events, which are involved in peripheral sensitization as well as control of inflammatory and nociceptive responses, may play a role in TMJ pathology.